Benchmarking: Specific Energy Consumption Models

Benchmarking: Bond/Barratt Circuit Specific Energy Consumption - Copper Mountain

• Morrison, R., Current Plant Conditions at Copper Mountain. Presentation to the BC/Yukon Branch Canadian Mineral Processors, November 29, 2012; Vancouver, Canada.

Result for default model conditions:

	Tonnage
Model	1455 t/h
Measured	1600 t/h
Difference	145 t/h
Difference	9.5%

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Benchmarking: Bond/Barratt Circuit Specific Energy Consumption - Fort Knox

• Magnuson, R.; Hallow, J.; Mosher, J.; Major, K., The Fort Knox Mill: Design, Commissioning and Operation. Proceedings of the SAG 2001 Conference, Vancouver, Canada.

Optimized Bond/Barratt SAB circuit (15% Essbm calibration factor).

Result for default model conditions:

	Etotal	WiO		Tonnage
Model	11.95	16.62	kWh/t	1,513	t/h
Measured	10.50	14.61	kWh/t	1,733	t/h
Difference	1.45	2.01	kWh/t	220	t/h
Difference	12.9%	13.8%		12.7%

Model predicts 12.9% harder than survey resulting in predicted throughput 12.7% lower than survey.

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Benchmarking: Bond/Barratt Circuit Specific Energy Consumption - Meadowbank

• Muteb, P. & Allaire, J., Meadowbank Mine Process Plant Throughput Increase, Proceedings of the Canadian Mineral Processors Annual General Meeting, Ottawa, Canada, January 2013.

Paper describes a "sick" SAG mill and the changes made to "bring it to health". The "healthy" mill conditions benchmark as follows:

• Actual SAG/ball motor powers (at shell): 3,168 kW / 4,105 kW
• Actual daily average throughput: 500 tonnes/hour
• Predicted SAG/ball motor powers (at shell): 3,096 kW / 4,182 kW
• Predicted nominal throughput: 500 tonnes/hour (0% difference)

	SAG	Ball Mill	total
Measured specific energy consumption, kWh/t	6.34	8.21	14.55
Predicted specific energy consumption, kWh/t	6.19	8.36	14.55
Difference, kWh/t	-0.15	0.15	0.00
Difference, %	-2.3%	1.8%	0.0%

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Benchmarking: Bond/Barratt Circuit Specific Energy Consumption - Santa Rita

Latchireddi, S. & Faria, E., Achievement of High Energy Efficiency in Grinding Mills at Santa Rita, Proceedings of the Canadian Mineral Processors Annual General Meeting, Ottawa, Canada, January 2013.

Faria, E. & Latchireddi, S., Commissioning and Operation of Milling Circuit at Santa Rita Nickel Operation, Paper #137: Proceedings of the International Autogenous Grinding, Semiautogenous Grinding and High Pressure Grinding Roll Technology Conference, Vancouver, Canada, September 2011.

	FAG	BM	Pebble Crusher	total
Measured specific energy consumption, kWh/t	9.55	7.28	0.34	17.18
Predicted specific energy consumption, kWh/t	9.78	8.33	0.39	18.50
Difference, kWh/t	0.23	1.05	0.05	1.32
Difference, %	2.4%	14.4%	14.7%	7.7%

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Benchmarking: Bond/Barratt Circuit Specific Energy Consumption - Macraes

Barns, K., Lane, G., Osten, K. & Scagliotta, N., Benchmarking Energy Efficiency - A Case Study at Macraes Gold Mine, Proceedings of the AusIMM MetPlant conference, Perth, Australia, September 2004.

Difference between model results and plant surveys:

		Survey 5	Survey 4	Survey 3	Survey 2	Survey 1	Overall Average
SAG specific power		-5.3%	-5.0%	6.3%	0.5%	2.2%	-0.2%
ball mill specific power		-6.3%	-4.7%	3.6%	1.9%	3.2%	-0.5%
total specific power		-6.8%	-3.8%	5.4%	1.4%	2.9%	-0.2%

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Benchmarking: Bond/Rowland SSBM Circuit Specific Energy Consumption - Boddington

The Bond/Rowland SSBM model was fit to the observed operation of the Boddington HPGR circuit. The fitting parameters are:

• E_ssbm calibration factor: (-0.13)
• Mechanical efficiency of HPGR crushers: 0.28.

Because the model is specifically fit to the Boddington data, it doesn't make any meaningful throughput predictions, but the following predictions are available:

• Ball mill operating work index reduction versus laboratory: 5% (microcracking/phantom cyclone effect)
• Secondary crusher WiO is 18.1 kWh/tonne (versus laboratory determination 27.7 kWh/t).

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Benchmarking: Bond/Barratt SABC Circuit Specific Energy Consumption - Kanowna Belle

Lunt, D.J., Thompson, A. and Ritchie, I. The Design and Operation of the Kanowna Belle Milling Circuit, SAG 1996, Pages 81-96.

	Survey	Optimized Model	Difference	Raw Model	Difference
ESAG	12.55 kWh/t	13.27 kWh/t	+5.7%	15.70 kWh/t	+25.1%
Eball	9.70 kWh/t	10.24 kWh/t	+5.6%	12.12 kWh/t	+24.9%
Epeb	0.99 kWh/t	1.04 kWh/t	+5.2%	1.23 kWh/t	+24.5%
Etotal	23.24 kWh/t	24.55 kWh/t	+5.6%	29.05 kWh/t	+25.0%

The Optimized Bond/Barratt SABC model better matches the survey than the Raw Bond/Barratt model.

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